Generally, in a pushbutton tuner, cores are moved in-and-out of coils by a core slide, the core slide is actuated by actuating links provided at positions interior of a tuner housing, namely, rearward of button slides, and the actuating links are actuated by setting pins provided on frequency regulating members, respectively, which are in turn provided on the button slides, respectively. Base end portions of the frequency regulating members are connected to the button slides by pivotal pins, respectively. Either of the setting pin and the pivotal pin has a cylindrical periphery extending in parallel with the axis thereof. Upon careful observation and study of such a known pushbutton tuner by the inventors of the present invention, it has been found that the known pushbutton tuner involves a possibility of tuning error (F deviation) in an actual selection operation and has such a disadvantage that a desired tuning cannot be always obtained.
The invention has been achieved upon study of these facts. The study has been first made as to why and how such tuning deviation or error is caused in the pushbutton tuner and it has revealed that while the frequency regulating member is fastened and held face to face by a head of the pivotal pin of cylindrical shape, it may possibly be rotated and since the angle of the frequency regulating member is required to be reset or changed, gaps are left around the periphery of the pivotal pin and from the face of the head, respectively, so that the possibility of tuning deviation or error is further increased. As to the setting pin, when it is brought into engagement with the edges of the actuating links for carrying out a selection operation, the frequency regulating member is caused to receive a considerable resistance at the tip end portion thereof under an unstable state at the base end thereof. Therefore, the setting pin will possibly disengage from the button slide so that stable and accurate selection operation cannot be expected.